Chemistry Unit Review - SNC2DI

Chemistry Unit Review - SNC2DI

Periodic Table

• Elements are organized by atomic number and properties.
• Periodic table is a table arranging elements in order of increasing atomic number; elements with similar chemical properties are placed in same vertical column, called a group or family.
• Each element has a unique atomic number, symbol, and atomic mass.

Bohr Diagrams of Atoms & Ions

• Atoms are composed of a nucleus (protons and neutrons) and electrons in orbits.
• Valence electrons determine chemical bonding.
• Ions are formed when atoms gain or lose electrons.
• Positive ions have lost electrons (cations).
• Negative ions have gained electrons (anions).
• Bohr diagrams illustrate electron arrangement in an atom or ion.

Ions and the Periodic Table

• Elements in the same group have similar electron arrangements and properties.
• Elements in groups 1, 2, and 17 typically form ions based on gaining or losing electrons.
• Some elements don't follow the pattern of regular ion charges. Exceptions need to be explained.

Chemical Families Names and Charges

• Knowledge of common ion charges required for naming and writing formulas.
• Group 1 (Alkali Metals): +1
• Group 2 (Alkaline Earth Metals): +2
• Group 17 (Halogens): -1

Ionic Compounds Naming & Formulas

• Ionic compounds are composed of positive and negative ions.
• Naming: name the cation (metal) first, then the anion (nonmetal).
• Writing the formula: use the number of charges on each ion to figure out the subscripts in the formula.

Polyatomic Compounds Naming & Formulas

• Polyatomic ions are groups of atoms with a charge.
• Naming: name the cation first, followed by the polyatomic ion.
• Writing the formula: write the number of charges based on the polyatomic ions required.

Molecular Compounds Naming and Formulas

• Molecular compounds are composed of nonmetals.
• Naming: prefixes indicate the number of each element.
• Writing formula: Prefixes indicate number of each type of atom.

Types of Chemical Reactions (Five Types)

• Synthesis: two or more substances combine to form one product.
• Decomposition: one substance breaks down into two or more substances.
• Combustion: a substance reacts rapidly with oxygen with heat and light.
• Single Displacement: one element replaces another element in a compound.
• Double Displacement: the cations of two ionic compounds switch places.

Law of Conservation of Mass

• Mass of reactants always equal mass of products.
• Matter cannot be created or destroyed in a chemical reaction.
• Essential to balance chemical equations.

Counting Atoms

• Determine the number of atoms in a given molecule/compound.

Balancing Equations

• Use coefficients to ensure the same number of atoms of each element on both sides of the equation.
• Essential to reflect the Law of Conservation of Mass.

Acids & Bases

• Acids: sour taste; corrosive; conduct electricity; change color of indicators.
• Bases: bitter taste; slippery texture; conduct electricity; change color of indicators.
• pH scale measures acidity or basicity.

pH Scale

• A scale from 0 to 14 to measure the concentration of H+ ions in a solution.
• pH of 7 is neutral.
• pH below 7 is acidic.
• pH above 7 is basic/alkaline.

This quiz covers key concepts in chemistry including the organization of the periodic table, Bohr diagrams of atoms and ions, and the properties of ions related to their position in the periodic table. Test your understanding of how elements interact and the significance of valence electrons.